1. Field of the Invention
The invention relates to the vapor phase catalytic oxidation of unsaturated aliphatic aldehydes to the corresponding unsaturated carboxylic acid.
2. Description of the Prior Art
Belgian Pat. No. 774,329 and Netherlands Patent Application 72-05595 disclose the use of a catalyst containing the elements Mo, V, W, Cr, and Cu, in various atom-mole ratios thereof, for the vapor phase catalytic oxidation of acrolein to acrylic acid. These publications indicate that the catalysts are prepared by a thermal treatment of a mixture of compounds of the elements Mo, V, W, Cr and Cu.
The terms % conversion, productivity and % selectivity which are employed herein with respect to the present invention are defined as follows: ##EQU1## WHEREIN A is as defined in equation Ia.